Rumors of a Facebook phone show no sign of abating, with the latest reports suggesting former Apple engineers who worked on the iPhone have been hired by Mark Zuckerberg to help build the device.

The New York Times’ Nick Bilton said his sources – who spoke on condition of anonymity – told him the company is hoping to launch its mobile phone “by next year.”

Bilton said in his report that Facebook had already hired “more than half a dozen Apple software and hardware engineers who worked on the iPhone, and one who worked on the iPad.”

While Facebook refused to offer any fresh comment on the latest reports surrounding the possibility of it entering the mobile phone market, it told the NYT that last year’s comments made to AllThngsD still stand: “We’re working across the entire mobile industry; with operators, hardware manufacturers, OS providers, and application developers,” the company said then.

Talk of a Facebook phone has been around for a couple of years, but it seems the rumor mill is in overdrive just now. Only last week news appeared that the social networking giant was also looking at buying the firm behind the Opera browser, a browser which could feasibly form part of a Facebook mobile OS. According to TheNextWeb, Opera bosses were “talking to potential buyers right now,” adding that there is currently a hiring freeze at the company, “a surefire sign that something big is about to happen – or at least that Opera wants something big to happen.”

Now that Facebook has shareholders to answer to, it must find ways to make money. Serious money. According to one Facebook employee who spoke to the NYT’s Bilton, Zuckerberg is concerned that if he doesn’t launch a mobile phone soon, “Facebook will simply become an app on other mobile platforms.”

Of course, launching a phone may prove to be the easiest part of the whole process. Getting people to actually buy it will be the real challenge, especially in a crowded market already dominated by Apple’s iPhone and Samsung’s Android-powered devices. Done right, however, and it could prove to be a lucrative money spinner for Zuckerberg and his team.